Kobayashi, Takashi

Abstract Background and Aims Despite that hepatic fibrosis often affects the liver globally, spatial distribution can be heterogeneous. This study aimed to investigate the effect of liver stiffness (LS) heterogeneity on concordance between MR elastography (MRE)‐based fibrosis staging and biopsy staging in patients with NAFLD. Approach and Results We retrospectively evaluated data from 155 NAFLD patients who underwent liver biopsy and 3 Tesla MRE and undertook a retrospective validation study of 169 NAFLD patients at three hepatology centers. Heterogeneity of stiffness was assessed by measuring the range between minimum and maximum MRE‐based LS measurement (LSM). Variability of LSM was defined as the stiffness range divided by the maximum stiffness value. The cohort was divided into two groups (homogenous or heterogeneous), according to whether variability was below or above the average for the training cohort. Based on histopathology and receiver operating characteristic (ROC) analysis, optimum LSM thresholds were determined for MRE‐based fibrosis staging of stage 4 (4.43, kPa; AUROC, 0.89) and stage ≥3 (3.93, kPa; AUROC, 0.89). In total, 53 had LSM above the threshold for stage 4. Within this group, 30 had a biopsy stage of <4. In 86.7% of these discordant cases, variability of LSM was classified as heterogeneous. In MRE‐based LSM stage ≥3, 88.9% of discordant cases were classified as heterogeneous. Results of the validation cohort were similar to those of the training cohort. Conclusions Discordance between biopsy‐ and MRE‐based fibrosis staging is associated with heterogeneity in LSM, as depicted with MRE.

SummaryBackgroundElobixibat, a novel inhibitor of apical sodium‐dependent bile acid transporter for treating chronic constipation, increases colonic bile acid concentrations, stimulating bowel function. However, it is not clear which bile acids are altered, or whether altered gut microbiota are associated with functional effects that may alter bowel function.AimsTo investigate the effects of elobixibat on changes in the faecal concentrations of total and individual bile acids and in faecal microbiota.MethodsThis was a prospective, single‐centre study. After baseline period, patients received 10 mg daily of elobixibat for 2 weeks. We evaluated the effects on bowel function, changes in faecal bile acid concentrations and composition of gut bacteria, before and after elobixibat administration.ResultsIn the 30 patients analysed, the frequency of pre‐ and post‐treatment bowel movements per fortnight was 7 and 10 (P < 0.001), respectively. The pre‐treatment faecal bile acid concentration increased significantly from 10.9 to 15.0 µg/g stool post‐treatment (P = 0.030), with a significant increase in faecal deoxycholic acid (pre‐treatment 3.94 µg/g stool to post‐treatment 5.02 µg/g stool, P = 0.036) and in glycine‐conjugated deoxycholic and chenodeoxycholic acids. Shannon index was significantly decreased, but there were no significant changes at the genus and phylum levels.ConclusionsShort term treatment with elobixibat increased the concentrations of total bile acids and deoxycholic acid and decreased the diversity of faecal microbiota. The biological effects of elobixibat are associated with its effects on secretory bile acids, rather than the structural changes of an altered faecal microbiota.